You obviously have Suitcase or some form of the Extensis font management installed because that's where your AI is failing. Your HD>Users>yourname>Library folder has been hidden in the last two iterations of Mac OSX. Do a Google search on how to show it. Look in HD>Applications>Adobe Illustrator CS5>PlugIns to see if the Suitcase plugin is installed there. Disk Utilities is in HD>Applications>Utilities.